selftests/mm: fix ARM related issue with fork after pthread_create

Following issue was observed while running the uffd-unit-tests selftest
on ARM devices. On x86_64 no issues were detected:

pthread_create followed by fork caused deadlock in certain cases wherein
fork required some work to be completed by the created thread. Used
synchronization to ensure that created thread's start function has started
before invoking fork.

[edliaw@google.com: refactored to use atomic_bool]
Link: https://lkml.kernel.org/r/20240325194100.775052-1-edliaw@google.com
Fixes: 760aee0b71e3 ("selftests/mm: add tests for RO pinning vs fork()")
Signed-off-by: Lokesh Gidra <lokeshgidra@google.com>
Signed-off-by: Edward Liaw <edliaw@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: sigbus-wp test requires UFFD_FEATURE_WP_HUGETLBFS_SHMEM

The sigbus-wp test requires the UFFD_FEATURE_WP_HUGETLBFS_SHMEM flag for
shmem and hugetlb targets. Otherwise it is not backwards compatible with
kernels <5.19 and fails with EINVAL.

Link: https://lkml.kernel.org/r/20240321232023.2064975-1-edliaw@google.com
Fixes: 73c1ea939b65 ("selftests/mm: move uffd sig/events tests into uffd unit tests")
Signed-off-by: Edward Liaw <edliaw@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Peter Xu <peterx@redhat.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: uffd-unit-test check if huge page size is 0

If HUGETLBFS is not enabled then the default_huge_page_size function will
return 0 and cause a divide by 0 error. Add a check to see if the huge page
size is 0 and skip the hugetlb tests if it is.

Link: https://lkml.kernel.org/r/20240205145055.3545806-2-terry.tritton@linaro.org
Fixes: 16a45b57cbf2 ("selftests/mm: add framework for uffd-unit-test")
Signed-off-by: Terry Tritton <terry.tritton@linaro.org>
Cc: Peter Griffin <peter.griffin@linaro.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: add separate UFFDIO_MOVE test for PMD splitting

Add a test for UFFDIO_MOVE ioctl operating on a hugepage which has to be
split because destination is marked with MADV_NOHUGEPAGE. With this we
cover all 3 cases: normal page move, hugepage move, hugepage splitting
before move.

Link: https://lkml.kernel.org/r/20231230025636.2477429-1-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Nicolas Geoffray <ngeoffray@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: add UFFDIO_MOVE ioctl test

Add tests for new UFFDIO_MOVE ioctl which uses uffd to move source into
destination buffer while checking the contents of both after the move.
After the operation the content of the destination buffer should match the
original source buffer's content while the source buffer should be zeroed.
Separate tests are designed for PMD aligned and unaligned cases because
they utilize different code paths in the kernel.

Link: https://lkml.kernel.org/r/20231206103702.3873743-6-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Nicolas Geoffray <ngeoffray@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: add uffd_test_case_ops to allow test case-specific operations

Currently each test can specify unique operations using uffd_test_ops,
however these operations are per-memory type and not per-test. Add
uffd_test_case_ops which each test case can customize for its own needs
regardless of the memory type being used. Pre- and post-allocation
operations are added, some of which will be used in the next patch to
implement test-specific operations like madvise after memory is allocated
but before it is accessed.

Link: https://lkml.kernel.org/r/20231206103702.3873743-5-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Nicolas Geoffray <ngeoffray@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: call uffd_test_ctx_clear at the end of the test

uffd_test_ctx_clear() is being called from uffd_test_ctx_init() to unmap
areas used in the previous test run. This approach is problematic because
while unmapping areas uffd_test_ctx_clear() uses page_size and nr_pages
which might differ from one test run to another. Fix this by calling
uffd_test_ctx_clear() after each test is done.

Link: https://lkml.kernel.org/r/20231206103702.3873743-4-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Nicolas Geoffray <ngeoffray@google.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: add uffd unit test for UFFDIO_POISON

The test is pretty basic, and exercises UFFDIO_POISON straightforwardly.
We register a region with userfaultfd, in missing fault mode. For each
fault, we either UFFDIO_COPY a zeroed page (odd pages) or UFFDIO_POISON
(even pages). We do this mix to test "something like a real use case",
where guest memory would be some mix of poisoned and non-poisoned pages.

We read each page in the region, and assert that the odd pages are zeroed
as expected, and the even pages yield a SIGBUS as expected.

Why UFFDIO_COPY instead of UFFDIO_ZEROPAGE? Because hugetlb doesn't
support UFFDIO_ZEROPAGE, and we don't want to have special case code.

Link: https://lkml.kernel.org/r/20230707215540.2324998-9-axelrasmussen@google.com
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gaosheng Cui <cuigaosheng1@huawei.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: fix two -Wformat-security warnings in uffd builds

The uffd tests generate two compile time warnings from clang's
-Wformat-security setting. These trigger at the call sites for
uffd_test_start() and uffd_test_skip().

1) Fix the uffd_test_start() issue by removing the intermediate
test_name variable (thanks to David Hildenbrand for showing how to do
this).

2) Fix the uffd_test_skip() issue by observing that there is no need for
a macro and a variable args approach, because all callers of
uffd_test_skip() pass in a simple char* string, without any format
specifiers. So just change uffd_test_skip() into a regular C function.

Link: https://lkml.kernel.org/r/20230606071637.267103-7-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Tested-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: add tests for RO pinning vs fork()

Add a test suite (with 10 more sub-tests) to cover RO pinning against
fork() over uffd-wp. It covers both:

(1) Early CoW test in fork() when page pinned,
(2) page unshare due to RO longterm pin.

They are:

Testing wp-fork-pin on anon... done
Testing wp-fork-pin on shmem... done
Testing wp-fork-pin on shmem-private... done
Testing wp-fork-pin on hugetlb... done
Testing wp-fork-pin on hugetlb-private... done
Testing wp-fork-pin-with-event on anon... done
Testing wp-fork-pin-with-event on shmem... done
Testing wp-fork-pin-with-event on shmem-private... done
Testing wp-fork-pin-with-event on hugetlb... done
Testing wp-fork-pin-with-event on hugetlb-private... done

CONFIG_GUP_TEST needed or they'll be skipped.

Testing wp-fork-pin on anon... skipped [reason: Possibly CONFIG_GUP_TEST missing or unprivileged]

Note that the major test goal is on private memory, but no hurt to also run
all of them over shared because shared memory should work the same.

Link: https://lkml.kernel.org/r/20230417195317.898696-7-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mika Penttilä <mpenttil@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: extend and rename uffd pagemap test

Extend it to all types of mem, meanwhile add one parallel test when
EVENT_FORK is enabled, where uffd-wp bits should be persisted rather than
dropped.

Since at it, rename the test to "wp-fork" to better show what it means.
Making the new test called "wp-fork-with-event".

Before:

Testing pagemap on anon... done

After:

Testing wp-fork on anon... done
Testing wp-fork on shmem... done
Testing wp-fork on shmem-private... done
Testing wp-fork on hugetlb... done
Testing wp-fork on hugetlb-private... done
Testing wp-fork-with-event on anon... done
Testing wp-fork-with-event on shmem... done
Testing wp-fork-with-event on shmem-private... done
Testing wp-fork-with-event on hugetlb... done
Testing wp-fork-with-event on hugetlb-private... done

Link: https://lkml.kernel.org/r/20230417195317.898696-5-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mika Penttilä <mpenttil@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: add a few options for uffd-unit-test

Namely:

"-f": add a wildcard filter for tests to run
"-l": list tests rather than running any
"-h": help msg

Link: https://lkml.kernel.org/r/20230417195317.898696-4-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Mika Penttilä <mpenttil@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: add uffdio register ioctls test

This new test tests against the returned ioctls from UFFDIO_REGISTER,
where put into uffdio_register.ioctls.

This also tests the expected failure cases of UFFDIO_REGISTER, aka:

- Register with empty mode should fail with -EINVAL
- Register minor without page cache (anon) should fail with -EINVAL

Link: https://lkml.kernel.org/r/20230412164548.329376-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: allow uffd test to skip properly with no privilege

Allow skip a unit test properly due to no privilege (e.g. sigbus and
events tests).

[colin.i.king@gmail.com: fix spelling mistake "priviledge" -> "privilege"]
Link: https://lkml.kernel.org/r/20230414081506.1678998-1-colin.i.king@gmail.com
Link: https://lkml.kernel.org/r/20230412164520.329163-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: workaround no way to detect uffd-minor + wp

Userfaultfd minor+wp mode was very recently added. The test will fail on
the old kernels at ioctl(UFFDIO_CONTINUE) which is misterious.
Unfortunately there's no feature bit to detect for this support.

Add a hack to leverage WP_UNPOPULATED to detect whether that feature
existed, since WP_UNPOPULATED was merged right after minor+wp.

Link: https://lkml.kernel.org/r/20230412164517.329152-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: move zeropage test into uffd unit tests

Simplifies it a bit along the way, e.g., drop the never used offset field
(which was always the 1st page so offset=0).

Introduce uffd_register_with_ioctls() out of uffd_register() to detect
uffdio_register.ioctls got returned. Check that automatically when testing
UFFDIO_ZEROPAGE on different types of memory (and kernel).

Link: https://lkml.kernel.org/r/20230412164404.328815-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: move uffd sig/events tests into uffd unit tests

Move the two tests into the unit test, and convert it into 20 standalone
tests:

- events test on all 5 mem types, with wp on/off
- signal test on all 5 mem types, with wp on/off

Testing sigbus on anon... done
Testing sigbus on shmem... done
Testing sigbus on shmem-private... done
Testing sigbus on hugetlb... done
Testing sigbus on hugetlb-private... done
Testing sigbus-wp on anon... done
Testing sigbus-wp on shmem... done
Testing sigbus-wp on shmem-private... done
Testing sigbus-wp on hugetlb... done
Testing sigbus-wp on hugetlb-private... done
Testing events on anon... done
Testing events on shmem... done
Testing events on shmem-private... done
Testing events on hugetlb... done
Testing events on hugetlb-private... done
Testing events-wp on anon... done
Testing events-wp on shmem... done
Testing events-wp on shmem-private... done
Testing events-wp on hugetlb... done
Testing events-wp on hugetlb-private... done

It'll also remove a lot of global references along the way,
e.g. test_uffdio_wp will be replaced with the wp value passed over.

Link: https://lkml.kernel.org/r/20230412164400.328798-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: move uffd minor test to unit test

This moves the minor test to the new unit test.

Rewrite the content check with char* opeartions to avoid fiddling with
my_bcmp().

Drop global vars test_uffdio_minor and test_collapse, just assume test them
always in common code for now.

OTOH make this single test into five tests:

- minor test on [shmem, hugetlb] with wp=false
- minor test on [shmem, hugetlb] with wp=true
- minor test + collapse on shmem only

One thing to mention that we used to test COLLAPSE+WP but that doesn't
sound right at all. It's possible it's silently broken but unnoticed
because COLLAPSE is not part of the default test suite.

Make the MADV_COLLAPSE test fail-able (by skip it when failing), because
it's not guaranteed to success anyway.

Drop a bunch of useless code after the move, because the unit test always
use aligned num of pages and has nothing to do with n_cpus.

Link: https://lkml.kernel.org/r/20230412164357.328779-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: move uffd pagemap test to unit test

Move it over and make it split into two tests, one for pagemap and one for
the new WP_UNPOPULATED (to be a separate one).

The thp pagemap test wasn't really working (with MADV_HUGEPAGE). Let's
just drop it (since it never really worked anyway..) and leave that for
later.

Link: https://lkml.kernel.org/r/20230412164352.328733-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: add framework for uffd-unit-test

Add a framework to be prepared to move unit tests from uffd-stress.c into
uffd-unit-tests.c. The goal is to allow detection of uffd features for
each test, and also loop over specified types of memory that a test
support.

Link: https://lkml.kernel.org/r/20230412164348.328710-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: UFFDIO_API test

Add one simple test for UFFDIO_API. With that, I also added a bunch of
small but handy helpers along the way.

Link: https://lkml.kernel.org/r/20230412164257.328375-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: split uffd tests into uffd-stress and uffd-unit-tests

In many ways it's weird and unwanted to keep all the tests in the same
userfaultfd.c at least when still in the current way.

For example, it doesn't make much sense to run the stress test for each
method we can create an userfaultfd handle (either via syscall or /dev/
node). It's a waste of time running this twice for the whole stress as
the stress paths are the same, only the open path is different.

It's also just weird to need to manually specify different types of memory
to run all unit tests for the userfaultfd interface. We should be able to
just run a single program and that should go through all functional uffd
tests without running the stress test at all. The stress test was more
for torturing and finding race conditions. We don't want to wait for
stress to finish just to regress test a functional test.

When we start to pile up more things on top of the same file and same
functions, things start to go a bit chaos and the code is just harder to
maintain too with tons of global variables.

This patch creates a new test uffd-unit-tests to keep userfaultfd unit
tests in the future, currently empty.

Meanwhile rename the old userfaultfd.c test to uffd-stress.c.

Link: https://lkml.kernel.org/r/20230412164244.328270-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>